All-solid photonic band gap fiber based distributed fiber optic pressure sensor

A novel distributed fiber optic pressure sensor based on an all-solid photonic band gap fiber is proposed and experimentally demonstrated. The sensor is fabricated by splicing a piece of the photonic crystal fiber (PCF) with a single-mode fiber (SMF), and the free end face of the PCF is filmed with a reflectivity of 99%. The cladding mode is excited at the fiber splice, resulting in the interference between the cladding mode and the core mode. The pressure position can be located by measuring the phase difference of the interferometer, and the pressure can be interrogated by measuring the height of the valley in the white-light optical spectrum. The experimental results show that the pressure and its position along the PCF can be simultaneously interrogated.